By Carmen Piernas and Barry M. Popkin

Trends In Snacking Among U.S.Children

ABSTRACT Nationally representative surveys of food intake in U.S.children show large increases in snacking between the 198991 to 199498 and 199498 to 200306 periods. Childhood snacking trends aremoving toward three snacks per day, and more than 27 percent ofchildrens daily calories are coming from snacks. The largest increaseshave been in salty snacks and candy. Desserts and sweetened beveragesremain the major sources of calories from snacks.

There has been little systematicexamination of recent eating pat-terns and longer-term trends, in-cluding those for childhoodsnacking. The rise of childhood

obesity coincides with a reported increase indaily snacking and a decline in the consumptionof three principal meals. Population-based stud-ies show increased food consumption related tothe snacking habit.1,2 More frequent snackinghas been positively associated with body weightin children.1 Other epidemiological and inter-vention studies in children and adolescents havelinked a more even distribution of food con-sumed throughout the day with lower bodymassindex (BMI).1,3,4 Most cross-sectional studies,after adjusting for body weight, have found thatobese children do not eat more than leanchildren.5

Snacks are readily available to all childrenand adolescents in several environments,6 andenergy-dense snacks have been linked with adecreased satiating (feeling of fullness) effect7,8

Greater intake of salty snacks and sweetenedcaloric beverages and increased portion sizesof snacks have been observed as potential con-tributors to daily food consumption.9,10 Conse-quently, these may play an important role inchildhood obesity. This study is focused onmore recent dynamics of snacking in all of itsdimensions.In this study, current snacking patterns and

key foods consumed during childhood were ex-amined along with long-term trends in snackingbehavior across four nationally representativesurveys of food intake in U.S. children over thepast three decades. Among our most importantfindings is an increase in thenumberof snackingevents in the past decade. The largest increasesin snacking events have been in salty snack andcandy consumption; however, desserts andsweetened beverages remain the major sourcesof calories from snacks.

Study Data And MethodsSURVEY DESIGN AND SAMPLE We selected31,337 children and adolescents, ages 218, fromfour nationally representative surveys of foodintake in the U.S. population: 12,231 respond-ents from the 19771978 Nationwide Food Con-sumption Survey (NFCS77); 3,148 from the19891991 Continuing Survey of Food Intakeby Individuals (CSFII89); 8,621 from the 19941996, 1998 Continuing Survey of Food Intakeby Individuals (CSFII98); and 7,337 from thejoint U.S. Department of Agriculture (USDA)NationalHealth andNutrition Examination Sur-veys (NHANES0306). More details are pre-sented elsewhere.1113

It is important to note that the methodologyused in NHANES is based on earlier CSFII meth-odologies. This is the first set of surveys that fullyintegrated the USDA and NHANES dietary data

doi: 10.1377/hlthaff.2009.0666HEALTH AFFAIRS 29,NO. 3 (2010): 2010 Project HOPEThe People-to-People HealthFoundation, Inc.

Carmen Piernas is apredoctoral student at theCarolina Population Center,University of North Carolinaat Chapel Hill.

Barry M. Popkin (popkin@unc.edu) is a professor ofnutrition at the CarolinaPopulation Center anddirector of theInterdisciplinary Center forObesity, University of NorthCarolina.

MARCH 2010 29:3 HEALTH AFFAIRS 1

FOOD & AGRICULTURE

collection systems.14 The USDA Food Composi-tion tables and methods of coding and probingwere used.

DIETARY RECORDS Dietary intake in the NFCSand in the CSFII89 was collected over three con-secutive days using a single interviewer-admin-istered twenty-four-hour recall. The CSFII98consisted of interviewer-administered twenty-four-hour recalls on two nonconsecutive days(three to ten days apart). NHANES0306 wasbased on two nonconsecutive days of twenty-four-hour dietary recall data (the day-one inter-view was conducted by trained dietary inter-viewers in the Mobile Examination Center,and the day two interview was conducted by tele-phone three to ten days after the first interview).For children younger than age twelve, informa-tion was obtained from the childs caregiver. Forcomparability, only the first two days of dietaryintake from each survey are included.

SNACK CONSUMPTION Snacks and meals wereself-defined in each survey, as was the timewheneach eating occasion began; they are comparablewith a second publication on adults.15 We com-bined snack events consumed in a fifteen-minuteperiod as a single snacking occasion. Subjectswho had snacks on any day were deemed snack-ers. Contributions to daily intake in subjectswho snacked onboth dayswere averaged. A largenumber of people reported consuming snackfood at a meal (for example, chips with lunch).We changed these reports of snacking to ameal iffood consumed during a meal was defined as asnack food. In the NFCS77, the CSFII8991, andthe CSFII9498, we found eating occasions de-fined as other or no answer. If a childwas notreported to have had three meals, those missingoccasionswere recodedasmeals according to theeating time. The remaining missing eating occa-sions were considered as snacks.We establishedthree principal meals, if possible, and then westudied the snacking behavior outside them, inall years surveyed. Our approach represents aconservative definition of snacking.

FOOD GROUPING SYSTEM TheUniversity ofNorthCarolinaChapel Hill approach begins withUSDA food groupings and breaks them downinto more detailed food groupings in a system-aticmethod.16We have linked all foods fromeachof theUSDA surveys together so that comparablefood compositions, Latin binomial names, andnutrient compositions are used for each food,because major changes in numbering and meas-urement quality have occurred over time. Thefood grouping system has been described else-where.17 The amount of energy provided by eachfood group for all individuals was calculated andthen divided by the total energy from snacking.Food groupings contributing the most to snack-

ing calories are reported.Consumption of water as a beverage was col-

lected differently across the surveys. Plain waterwas added as a food item in 2003, accounting forup to 5 percent of all reported foods in 200306versus0percent in all theotherprevious surveys.To ensure comparability, water as a food itemwas deleted in all years.

STATISTICAL ANALYSIS Individuals were strati-fied by age: ages 26, ages 712, and ages 1318. Differences testing, by a students t-test(which allows the use of a small number of mea-surements to estimate what may be true of thewhole population), used STATA, version 10, atype of data analysis and statistical software, toweight the results and control standard errorsfor sample design effects. We used survey com-mands to account for survey design, weighting,and clustering. A p (probability) value of 0.01was set for statistical significance. (A p valueof less than 0.05 is considered statistically sig-nificantthat is, not likely to be due to chancealone.)

Study ResultsCHARACTERISTICS OF SNACKERS The percentages ofchildren consuming snacks by sociodemo-graphic characteristics were always higher than97 percent for each category in 200306. Weidentifiedmales, non-Hispanicwhites,withhighhousehold income level (greater than 350 per-cent of the federal poverty level) and education(high school diploma or higher) as the catego-ries with slightly higher percentages of snackers(unreported results).

DYNAMIC CHANGES IN SNACKING BEHAVIOR Dailysnacking among children has increased mark-edly over the periods studied (Exhibit 1). Theprevalence of snackers among all children (ages218) increased from 74 percent in 197778 to98 percent in 200306. Major increases wereobserved from 1989 to 1994 and from 1994 to2006.We found small differences in percentagesof snacking among the age groups for eachsurvey.

INCREASES IN SNACKING HABITS OVER TIME Sig-nificant changes in snacking behavior were ob-served for all children from 197778 to 200306(around 1.11more snacks perday). Children ages26 accounted for the highest number of snacksper day and the largest increment from 1977 to2006 (approximately 1.41 events more). The lat-est increment in number of snacks per day hasbeen linked with a small decline in calories persnacking event; however, the increased energyper snack from 1977 to 2006was still significant.Grams consumed per snack event increased sig-nificantly from 1977 to 2003 in all age groups

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2 HEALTH AFFAIRS MARCH 2010 29:3

(around 50 gramsmore per snack). The changesin grams consumed per snack from 1994 to 2003were not significant except for children ages 1318 (around 76 grams more). Regarding the totalenergy intake coming from snacks, we observedthat all children consumed approximately 168more calories a day from snacking from 1977to 2006 (Appendix Exhibit 1).18

From 197778 to 200305, the percentage ofsnacking calories increased to 27 percent in allchildren (Exhibit 2). Regarding daily energy in-take, children increased their caloric intake by113 calories per day from 1977 to 2006. The larg-est increasewas found among children ages 26,who consumed 182 calories more per day.

TRENDS IN ENERGY DENSITY AND FOOD SOURCES

Within each age group, snacking energy densitymaintained its trends over the periods covered(Exhibit 3). Forchildrenages712 and1318, theenergy density of beverages from snacks andmeals showed a significant decreased trend overthe periods studied.Important shifts in themajor snacking sources

from 1977 to 2006 are shown in Exhibit 4.Although consumption of desserts decreasedin 200306, they remained the main contribu-tors to snacking calories in 2006. The secondmain source of snacking energywas salty snacks,which experienced the largest increase in the

past three decades. Consumption of candy andfruit drinks also increased over the periodscovered. We observed an important shift fromhigher intake of fresh fruit in 1977 to more fre-quent consumption of fruit juice in 2006. Con-sumption of sweetened beverages showed littlechange over this period but was found to be thethird-highest contributor to snacking energyin 2006.

DiscussionThis study has documented important increasesin snacking behavior across all child age groupsduring the past three decades. Children in theUnited States, especially the young, are consum-ing almost three snacks per day, and snackingaccounted for up to 27 percent of childrens dailycaloric intake in 2006.Our results showedmajorrises in snacking prevalence and caloric intakefrom 198991 to 199498 and again from 199498 to 200306. Important shifts toward con-suming more salty snacks and candy have beenreported, although sweetened beverages anddesserts remained the major snacking sources.Previous studies in children and young adults

found that the contribution of snacking to thetotal energy intake accounted for up to 25 per-cent and 23 percent, respectively, in 1996.19,20

EXHIBIT 1

Percentage Of U.S. Children Consuming Snacks Over A Two-Day Period, Selected Years 19772006

Perc

ent

SOURCE Content based on authors assessments. NOTE Percentage of children consuming snacks on day 1 of interview, day 2 of inter-view, or both.

MARCH 2010 29:3 HEALTH AFFAIRS 3

These studies also reported an increased trend inthe total calories coming from snacks and in thetotal number of snacking occasions. Our resultsare consistent with trends from previous re-search, except for the important jump in snack-ing behavior in this decade.

ENERGY DENSITY Some important key issues re-lated to the energy intake showed interestingtrends over the years studied. First, the energydensity of snacks was constant over the yearsstudied. Other findings in young adults reportedan increasing trenduntil 1996.20 Additional com-ponents of the increased energy intake fromsnacking are the grams and calories consumedper snack event.21 We found increased portionsizes of snacks in terms of grams; however, be-cause of the increased intake of caloric bever-ages, there was a small decrease in calories persnack from199498 to 200306, consistentwithearlier studies.22 However, without further re-search, it is unclear whether this most recentperiod represents a shift toward lower portionsizes, or just the combination of more smallersnacks and more caloric beverages overall. Fur-thermore, there is minimal evidence on thehealth effects of these snacking changes.23,24

This study found a meaningful increase in theintake of energy-dense salty snacks and candy assources of snacking energy. Also, children areconsumingmore beverages, such as fruit drinks,sport drinks, and fruit juice, while decreasingfruit as a snacking source. Desserts remainedthe major snacking source, consistent with pre-vious work.20 However, the smaller, less rep-resentative Bogalusa Heart Study found decreas-ing grams consumed from fruit juices and fruit,desserts, and candy from 1973 to 1994 in ten-year-olds.25

INCONSISTENT DEFINITIONS These results maydiffer because snack and meal definitions havenot been clearly established. In our study, wedefined snacks as eatingoccasions outsidemeals.Foods defined as snack foods but consumedwitha meal were recoded as meals.We also combinedall snack food consumed within fifteen minutesas one snacking event. A small proportion offood with missing designations of eating occa-sions were assigned first to meals, and the re-maining were considered as snacks (there was asmall effect of a shift in prevalence of less than atenth of a decimal place). This conservative def-inition allowedus to define three principalmeals

EXHIBIT 2

Contribution Of Snacking To Total Daily Energy Intake, By Year And Age Group, Selected Years 19772006

Energy from snacksEnergy from meals

Kilocalories per day

aa

b

aa

b

aa

a, b

aa

a

b

SOURCE Content based on authors assessments. NOTES Red bars represent the percentage of energy from snacks. Standard errors forthe total kilocalories for snacking are found in Appendix Exhibit 1, as in Note 18 in text. a Significant differences in snacking kilo-calories from the previous year (students t-test; p < 0:01). b Significant differences in snacking kilocalories between 197778 and200306 (students t-test; p < 0:01).

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4 HEALTH AFFAIRS MARCH 2010 29:3

and then study snacking outside of meals for allyears surveyed. Different researchers have de-fined snacks according to the name identifiedby the respondent, time of day, or type of food.Snacking foods have even been counted as sin-gle eating occasions within a unique time inter-val.2628 Although there is no current consensusabout definitions, our approach may be morelinked to the way we understand the metabolicconsequences of foods eaten together at oneshort period occasion.

DAYS OF SNACKING SURVEYED Days of intake sur-veyed may also be influencing disparities be-tween studies. To be consistent, we used twodays of intake to create comparable measure-ments over time. This allowed us to have a closerapproximation of usual intake. Further, wefound that the third day of snacking data forthe two earlier studies was different from theother days and probably represented underesti-mates of snacking. The NFCS78 and CSFII89 re-ported that only 4 percent of subjects had snacks

on day three, and this last day is suspected to begreatly underreported.19

OTHER LIMITATIONS Other limitations inherentin this study are related to the use of differentsurveys. Changes in surveys from the 1980s tothe 1990s have been important, although sub-sequent changes in the number of passes andprobes have been much smaller. As with allUSDA surveys, theNHANES0306methodologyis the same as that of the CSFII developed by theUSDA, since the surveys were merged with theUSDA taking the lead on the diet component.14

This was the reason for adding the second day ofdietary record for NHANES beginning in 2003.Unfortunately, no bridging study between the1980s and 1990s nor between the 1990 and20032006 surveymethods exists, aswas under-taken earlier by the USDA.29 The University ofNorth CarolinaChapel Hill food grouping sys-tem developed by this team was used to linkdifferent foods coded and collected in the firstsurvey with the foods consumed in the last peri-

EXHIBIT 3

Trends In Energy Density Of Meals And Snacking Occasions In U.S. Children Ages 218, Selected Years 19772006

Age group/eating occasion

Energy density (kcal/gram)a

197778 198991 199496 200306Ages 26Total snacking 1.34 1.59b 1.34c 1.28c

Total meals 1.15 1.15 1.15 1.17Snacking food 2.76 2.86 2.55b,c 2.54b,c

Meal food 1.91 1.90 1.90 1.96Snacking beverages 0.48 0.47 0.48 0.47Meal beverages 0.49 0.48 0.48 0.49

Ages 712Total snacking 1.42 1.56 1.48 1.42Total meals 1.21 1.22 1.20 1.25b,d

Snacking food 2.78 2.68 2.78 2.79Meal food 1.93 1.99 2.02b 2.09b,c,d

Snacking beverages 0.47 0.42b 0.43b 0.42b

Meal beverages 0.50 0.48b 0.46b 0.45b,c

Ages 1318Total snacking 1.28 1.30 1.23 1.32Total meals 1.20 1.20 1.18 1.21Snacking food 2.84 3.00 2.87 2.96Meal food 1.96 2.07b 2.05b 2.16b,c,d

Snacking beverages 0.43 0.40b 0.40b 0.40b

Meal beverages 0.46 0.42b 0.41b 0.40b

Ages 218Total snacking 1.34 1.49b 1.35c 1.34c

Total meals 1.19 1.19 1.18 1.21b,d

Snacking food 2.80 2.83 2.73 2.78Meal food 1.94 1.99b 1.99b 2.08b,c,d

Snacking beverages 0.46 0.43b 0.44b 0.43b

Meal beverages 0.48 0.46b 0.45b 0.44b,c,d

SOURCE Content based on authors assessments. aTotal snacking and total meals combine food plus beverages. bSignificantly differentfrom 197778 (students t-test, p < 0:01). cSignificantly different from 198991 (students t-test, p < 0:01). dSignificantly differentfrom 199496 (students t-test, p < 0:01).

MARCH 2010 29:3 HEALTH AFFAIRS 5

ods, ensuring consistently high-quality esti-mates of nutrient values over time.16

CONCLUSION Our findings suggest that childrenages 218 are experiencing important increasesin snacking behavior and are moving toward a

consumption pattern of three meals plus threesnacks per day. This raises the question ofwhether the physiological basis for eating is be-comingdysregulated, as our children aremovingtoward constant eating.

Financial support for this paper wasprovided by the National Institutes ofHealth.

NOTES

1 Nicklas TA, Yang SJ, Baranowski T,Zakeri I, Berenson G. Eating pat-terns and obesity in children: theBogalusa Heart Study. Am J PrevMed. 2003;25(1):916.

2 Nielsen SJ, Siega-Riz AM, PopkinBM. Trends in energy intake in U.S.between 1977 and 1996: similarshifts seen across age groups. ObesRes. 2002;10(5):3708.

3 Nicklas TA, Morales M, Linares A,Yang SJ, Baranowski T, De Moor C,et al. Childrens meal patterns havechanged over a 21-year period: theBogalusa Heart Study. J Am DietAssoc. 2004;104(5):75361.

4 Summerbell CD, Moody RC, Shanks

J, Stock MJ, Geissler C. Relationshipbetween feeding pattern and bodymass index in 220 free-living peoplein four age groups. Eur J Clin Nutr.1996;50(8):5139.

5 Rocandio AM, Ansotegui L, ArroyoM. Comparison of dietary intakeamong overweight and non-over-weight schoolchildren. Int J ObesRelat Metab Disord. 2001;25(11):16515.

6 Butler D, Pearson H. Dietary advice:flash in the pan? Nature. 2005;433(7028):7946.

7 Flood J, Roe L, Rolls B. The effect ofincreased beverage portion size onenergy intake at a meal. J Am Diet

Assoc. 2006;106(12):198490.8 Rolls BJ, Roe LS, Meengs JS. Re-

ductions in portion size and energydensity of foods are additive and leadto sustained decreases in energy in-take. Am J Clin Nutr. 2006;83(1):117.

9 Tholin S, Lindroos A, Tynelius P,Akerstedt T, Stunkard AJ, Bulik CM,et al. Prevalence of night eating inobese and nonobese twins. Obesity(Silver Spring). 2009;17(5):10505.

10 Stunkard AJ, Allison KC, OReardonJP. The night eating syndrome: aprogress report. Appetite. 2005;45(2):1826.

11 Rizek R. The 197778 Nationwide

EXHIBIT 4

Proportion Of Snacking Calories From Food Groupings In U.S. Children Ages 218, Selected Years 19772006

Percent of daily energy from snacks

Fruit drinksSports drinks

Fruit juiceFresh fruit

High-fat milkLow-fat milk

High-fat dairyLow-fat dairy

High fat Low fat

High fatLow fat

CandyNuts and seeds

Ready-to-eat cereal

SOURCE: Content based on authors assessments. NOTES The University of North CarolinaChapel Hill food grouping system was used toselect the main food groupings. Desserts include cakes, cookies, pies, bars, ice cream, and gelatin desserts. Salty snacks include crack-ers, chips, popcorn, and pretzels. High-fat desserts and salty snacks were defined as those with more than 5 grams of fat per 100 gramsof food.

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6 HEALTH AFFAIRS MARCH 2010 29:3

Food Consumption Survey. FamEcon Rev. 1978;4:37.

12 U.S. Department of Agriculture,Beltsville Human Nutrition ResearchCenter, Food Surveys ResearchGroup. The Continuing Survey ofFood Intakes by Individuals (CSFII)and the Diet and Health KnowledgeSurvey (DHKS) 198991 (surveydocumentation) [Internet]. Belts-ville (MD): USDA; [cited 2010 Feb10]. Available from: http://www.ars.usda.gov/Services/docs.htm?docid=7797

13 U.S. Department of Agriculture,Beltsville Human Nutrition ResearchCenter, Food Surveys ResearchGroup. What we eat in America,NHANES 20032004. Beltsville(MD): USDA; 2003.

14 Moshfegh AJ. The National Nutri-tion Monitoring and Related Re-search Program: progress andactivities. J Nutr. 1994;124(9 Suppl):1843S5S.

15 Piernas C, Popkin B. Snackingtrends in U.S. adults between 1977and 2006. J Nutr. Forthcoming.

16 Popkin B, Haines P, Siega-Riz A.Dietary patterns and trends in theUnited States: the UNC-CH ap-proach. Appetite. 1999;32(1):814.

17 Duffey K, Gordon-Larsen P, JacobsD, Steffen L, Van Horn L, PopkinBM. Differences in dietary patterns

account for differential metabolicsyndrome risk among consumers ofdiet beverages: the CARDIA Study.Unpublished paper; 2008.

18 The Appendix Exhibits are availableby clicking on the Appendix Exhibitslink in the box to the right of thearticle online.

19 Jahns L, Siega-Riz AM, Popkin BM.The increasing prevalence of snack-ing among U.S. children from 1977to 1996. J Pediatr. 2001;138(4):4938.

20 Zizza C, Siega-Riz AM, Popkin BM.Significant increase in young adultssnacking between 19771978 and19941996 represents a cause forconcern! Prev Med. 2001;32(4):30310.

21 Schwartz MB, Novak SA, Fiore SS.The impact of removing snacks oflow nutritional value from middleschools. Health Educ Behav. 2009Dec; 36(6):9991011.

22 Smiciklas-Wright H, Mitchell DC,Mickle SJ, Goldman JD, Cook A.Foods commonly eaten in the UnitedStates, 19891991 and 19941996:are portion sizes changing? J AmDiet Assoc. 2003;103(1):417.

23 McGraw SA, Stone EJ, Osganian SK,Elder JP, Perry CL, Johnson CC, et al.Design of process evaluation withinthe Child and Adolescent Trial forCardiovascular Health (CATCH).

Health Educ Q. 1994;Suppl 2:S526.24 Troiano RP, Flegal KM. Overweight

children and adolescents: descrip-tion, epidemiology, and demo-graphics. Pediatr. 1998;101(3 Pt 2):497504.

25 Jago R, Baranowski T, Watson K,Baranowski JC, Nicklas T, Zakeri IF.Relationships between maternal andchild cardiovascular risk factorsethnic differences and lack of influ-ence of physical activity. ArchPediatr Adoles Med. 2004;158(12):112531.

26 Kant AK, Graubard BI. Seculartrends in patterns of self-reportedfood consumption of adult Ameri-cans: NHANES 19711975 toNHANES 19992002. Am J ClinNutr. 2006;84(5):121523.

27 Howarth NC, Huang TT, Roberts SB,Lin BH, McCrory MA. Eating pat-terns and dietary composition inrelation to BMI in younger and olderadults. Int J Obes (Lond). 2007;31(4):67584.

28 Summerbell CD, Moody RC, ShanksJ, Stock MJ, Geissler C. Sources ofenergy from meals versus snacks in220 people in four age groups. Eur JClin Nutr. 1995;49(1):3341.

29 Guenther PMBBP, Vizoli TL Jr.Separating fact from artifact inchanges in nutrient intake over time.J Am Diet Assoc. 1994;94:2705.

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